7 Class 1 General Electronic Products 级别1 普通电子产品Includes products suitable for applications where the major requirement is function of the completed assembly.包括适合应用

8 Class 2 Dedicated Service Electronics Parts 级别2 专业电子产品Includes products where continued performance and extended life are required, and for which uninterrupted service is desired, but not critical. Typically the end-use environment would not cause failures.包括持续性能和寿命要求，

9 Class 3 High Performance Electronics Products 级别3 高性能电子产品Includes products where continued high performance or performance-on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must function when required, such as life support or other critical systems.

10 What Class Does MCG Use? MCG使用等级Typically MCG uses Classes 2 and 3.Based on IPC-A-610 Acceptability of Electronic Assemblies.The customer ultimately determines the class to which the assembly is evaluated.MCG主要运用2和3等级基于IPC-A-610电子装配客户最终决定产品等级

16 The Conical Tip锥形铁芯 Used for small pads with a small amount of solder.Directs the heat into a small area.Minimal contact = minimal heat transfer.适用于小的键合点和少量的焊料直接加热至小的地方小的接触=小的热量传递

17 The Chisel Tip凿形铁芯Evenly distributes the heat between the pad and the lead.Used to solder multilayer boards which require a faster transfer of heat to a large surface area.Larger contact = larger heat transfer.

18 Changing Soldering Tips 换铁芯Tips may be replaced for different applications.Tips should be kept clean and tinned at all times.铁芯更换的不同运用铁芯必须清洁，表面要镀锡

19 Solder Wire焊锡丝 Different diameters of solder.There are different ratios of Tin, and Lead, compounds.MCG recently began using Lead-Free solder to comply with RoHS.There are different types of flux cores for different applications.不同直径的焊料不同比率的锡，和复合成分MCG最近开始使用符合ROHS的无铅焊料不同运用条件下的不同焊料

20 Solder Alloys 合金焊料 不同元素的比例决定熔点 焊料应该有个低的熔点，材料才能被连接Solder may include metals such as tin, silver, copper, bismuth, indium, zinc & lead.The ratio of each element determines melting point.The solder should have a lower melting point than the metals that are being joined.焊料材料包括：锡，银，铜，铋，铟，锌和主成不同元素的比例决定熔点焊料应该有个低的熔点，材料才能被连接

24 Solder Melting PointsMCG’s lead free solder has a melting point of 219°C (426°F), which is 36°C (nearly 100°F) higher than the former solder used.MCG无铅焊料的熔点是219°C (426°F), 比普通焊料高36°C (几乎100°F)Plastic stage is important because this is the range that solder joint should not be disturbed while solidifying.塑性很重要因为这是焊接过程中不容易被破坏。

25 Solder Fluxes 助焊剂Most hand soldering type solders contain flux in the solder core.多数的手工焊料都含有助焊剂。May also be a liquid that is applied to the connection before soldering.Used to reduce the oxides on the metals before the joints are soldered.Also aids in forming the “heat bridge”.May leave behind residue that should be cleaned away.

31 Types of Fluxes at MCGWe currently use RA1544, RMA 197 and 961 no-clean flux.Consider 959T (RoHS ready) in place of the 961.RMA186 (RoHS ready) flux would be an option of we need something more active (replace RMA197).RMA197 flux is currently used for Defense-Aerospace applications.The flux-core solder we use contains the 275 no-clean flux.

35 Lead Prep – TinningThe wire should be “tinned” before soldering it to the terminalTin the wire using a soldering iron & solder.An alternate and sometimes preferred method would be to use an RA flux and dip in a solder pot.

36 Lead Prep – Tinning (cont)Stranded wire is uniformly coated with a thin coat of solder with the individual strands of the wire easily visible.Un-tinned length of strands from end of insulation is not greater than one wire diameter.The solder wets the tinned portion of the wire and penetrates to the inner strands of stranded wire.

37 Lead Prep – Tinning (cont)AcceptableSome solder wicking as long as the solder does not extend to a portion of the wire that is required to remain flexible.Strands are not discernible but excess solder does not affect form, fit or function.Solder does not penetrate to the inner strands of the wire.

38 Lead Prep – Tinning (cont)Acceptable – Class 1Process Indicator – Class 2Defect – Class 3Pinholes, voids or nonwetting exceeds 5% of the area required to be tinned.Length of untinned strands from end of insulation is greater than one wire diameter.Solder does not wet the tinned portion of the wire.Stranded wire is not tinned prior to attachment to terminals or forming splices.Defect – Class 2, 3

39 Lead Prep – Tinning (cont)Solder wicking extends into the portion of wire that is required to remain flexible after soldering.Solder build-up or icicles within tinned wire area that affect subsequent assembly steps.Defect – Class 1, 2, 3

40 Bending the Wire Use round nose pliers that do not have serrated jaws.Bend the wire to the proper radius.

42 Solder Cups (cont)Solder cups should have the wire(s) inserted straight in and contact the back wall for the full depth of the cup.

43 Solder Cups (cont)Here multiple wires are inserted the full depth of the cup.Each wire must contact the back of the solder cup.

44 Splicing ConnectionsButt joint lengths should be at least three time their width.Wires should be tinned prior to splicing.Add flux to connection prior to fusing.Do not disturb wire position while joint is solidifying.A preferred method is to form a good mechanical connection prior to soldering.

45 Magnet Wire ConnectionWire is stripped per the specified process.Wrap the magnet wire around the tinned lead wire a minimum of three full revolutions.

46 Insulation Damage Target – Class 1, 2, 3Insulation has been trimmed neatly with no signs of pinching, pulling, fraying, discoloration, charring or burning.A slight uniform impression in the insulation from the gripping of mechanical strippers.Chemical solutions, paste, and creams used to strip solid wires do not cause degradation to the wire.Slight discoloration of insulation resulting from thermal processing is permissible, providing it is not charred, cracked or split.Acceptable – Class 1, 2, 3

49 Solder Pad Provides a conductive area for the lead of a component.Specifications determine how close they can be to other pads or traces.May also be called a “land”.

50 Soldering ComponentsSoldering is performed on the solder side of the board.By working on the solder side, the components are less likely to be damaged.The opposite side of the PCB is referred to as the component side.

52 SolderingThe solder heat bridge transfers heat rapidly from the tip to the connection.Molten solder forms a bridge or “avenue” to the connection to rapidly transfer heat.

53 The “Wetting” ProcessMetals are coated with “oxides” from the air and must be removed before the metals can be joined properly.The flux chemically reduces or removes these oxides to promote “wetting”.The solder flows after the flux and joins the two metals.

54 The Soldering Process The tip is placed between the pad and the lead.Form the solder heat bridge.

55 The Soldering Process (cont)Solder is moved to the opposite side of the lead.The fillet is formed.

56 The Soldering Process (cont)Solder wire is removed first.Then the tip is removed.

57 The Intermetallic BondIf the soldered joint has been properly wetted, an “intermetallic bond” is created.An “intermetallic bond” is the joining of two metals.

58 The Solder “Fillet”A properly wetted solder joint produces a “fillet”.The fillet should normally be concave, feathering out to a thin edge.

59 Soldering the Solder CupDo not move wire until solder has solidified.No solder splash or overflow onto the outside of the cup terminal.Minimum insulation gap may contact the solder, but shall not be covered by solder.

66 Inspecting Solder Cups (cont)Thin film of solder on the outside of the cup.Solder fill 75% or more.Solder buildup on the outside of the cup, as long as it does not affect form, fit, or function.Acceptable – Class 1, 2, 3

67 Inspecting Solder Cups (cont)Maximum insulation gap should be less than 2 times the wire diameter, or 1.5mm, whichever is larger. Target clearance is 1 wire diameter.ExampleA 30 Ga. teflon insulated wire has a diameter over the insulation of .029”. This would abide by the 1.5mm (.059”) limit or less.A 16 Ga. teflon insulated wire has a diameter over the insulation of .075”. The 2x guideline would be used so the max allowable insulation clearance would be .150” or less.

69 Insulation Clearance Acceptable – Class 1, 2, 3The insulation clearance (C) is two wire diameters or less including insulation or 1.5 mm [0.059 in] (whichever is greater).Insulation clearance (C) does not permit violation of minimum electrical clearance to adjacent conductors.The insulation is in contact with the solder but does not interfere with formation of an acceptable connection.Acceptable – Class 1, 2, 3

71 Through Hole ConnectionsDefect Class 3,Acceptable Class 2 if:The plated through hole (PTH) is connected to thermal or conductor planes that act as a thermal heat sinks.The component lead is discernable in the Side B solder connection.The solder fillet on Side B has wetted 360° of the PTH barrel wall and 360° of the lead.

74 The Cold Solder JointIn the cold solder joint, the solder was melted by the iron, but did not bond to the parts to be soldered.The joint did not exhibit proper wetting.This is an unacceptable solder joint.

75 Non-Wetting A properly wetted solder joint produces a fillet.If the oxides are not reduced, a quality solder joint cannot be produced.Insufficient heat can also cause poor wetting.This is a rejectedsolder joint.

77 The Overheated Solder JointThe overheated solder joint has a chalky, dull, or pitted finish.Caused by excessive dwell time (leaving the iron in contact too long), or excessive heating cycles.This is an Unacceptable Solder Joint.

78 The Disturbed JointIn the disturbed joint, the board or the part was moved while the solder was solidifying.This is an unacceptable solder joint.Disturbed Joint

79 The Disturbed Joint (cont)DefectsDisturbed solder joint characterized by stress lines from movement in the connection.Fractured or cracked solder.

80 The BlowholeIn a blowhole defect, gas has escaped through the solder while hardening.This can be caused by moisture or solvent on the board.This is an unacceptable solder joint.Blow holes are acceptable if they do not reduce solder connections below minimum requirements.

81 The Solder BridgeThe solder bridge is caused by using too much solder on the connection.The solder has “bridged” or connected to another joint causing a short.This is and unacceptable solder joint.Solder Bridge

83 Soldering Anomalies (cont)Solder balls violate minimum electrical clearance.Solder balls can migrate because they are not entrapped in conformal coating.

84 The Solder Icicle or ProjectionThe solder icicle is usually caused by improper removal of the iron or excessive “dwell time”.Also can be caused by insufficient flux.This is an unacceptable solder joint.Solder Icicle

89 Soldering Anomalies (cont)Acceptable - Class 1, 2, 3For connections made with lead-free alloys:The bottom of the tear is visible.The tear or shrink hole does not contact the lead, land or barrel wall.Defect – Class 1, 2, 3Shrink holes or hot tear in connections made with SnPb solder alloys:The bottom of the shrink hole or hot tear is not visible.The tear or shrink hole contacts the lead or land.

91 Quiz QuestionsWhich element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F)Solder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F)After the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.

92 Quiz Questions When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?

94 Quiz Answers Which element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F)Solder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F)After the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.

95 Quiz Answers Which element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F)Solder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F)After the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.True

96 Quiz Answers Which element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F) TrueSolder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F)After the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.False

97 Quiz Answers Which element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F) TrueSolder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F) FalseAfter the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.

98 Quiz Answers Which element was removed from solder alloys under RoHS?CopperMercuryTinLeadSolder wire comes in several different diameters. (T or F) TrueSolder joints with a wetting angle greater than 90° are ok if removed with a side cutter. (T or F) FalseAfter the insulation is remove from lead wire, what should be done to the strands prior to further processing?Check for obvious damage to the insulation caused by the stripping operation.Tin the lead wire using the specified process.Check for obvious damage to the wire strands caused by the stripping operation.All of the above.A “heat bridge” is used to?Test the flux for melting point.Rapidly transfer heat to a connection during soldering.Prevent dangerous driving conditions in freezing weather.

99 Quiz Answers When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?

100 Quiz Answers When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?

101 Quiz Answers When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?

102 Quiz Answers When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?

103 Quiz Answers When completing a solder joint which is removed first?The solder iron tipThe solder wireThe component leadWhich solder joint generally has a shiny finish?A solder joint soldered with solder containing lead.A solder joint that had heat applied too long.A solder joint solder with lead-free solder.If a stray wire strand is outside a through hole or solder cup, this is:A defect because it may violate minimum electrical clearance.A defect because the connection integrity is compromised.OK, because that is what side cutters are for.a) and b) above.Which flux is the least reactive and likely to leave less residue?Type “R”Type “RA”Type “RMA”Which solder tip generally transfers heat faster, a conical or chisel tip?The Chisel Tip